1. Field Of The Invention
The invention relates to 3-(2-hydroxybenzoyloxy)-4-(trimethylammonio)-butyric acid betaine of formula: ##STR1## in its racemic form and optically active forms and its pharmaceutically acceptable salts as well as a process for its production. 3-(2-Hydroxybenzoyloxy)-4-(trimethylammonio)-butyric acid betaine is a salicylic acid derivative with therapeutic properties as an ester of the salicylic acid with carnitine (salicyloyl carnitine).
2. Prior Art
Salicylic acid is used in the form of its acetyl derivative to a large extent as an analgesic. Although this acetyl derivative (known, i.a., as Aspirin.RTM.) was originally developed to reduce disturbing side effects of the salicylic acid already known earlier, nevertheless, it is affected by several properties which limit its possibilities of use. Above all, its low water solubility, in particular in an acid medium, for example, in gastric juice, is one of these unfavorable properties. With oral administration of aqueous solutions, the low solubility can lead to the precipitation of the active ingredient in the stomach. This effect is undesirable not only in individuals with a sensitive or previously damaged gastric mucous membrane, since it can lead to serious side effects in these individuals, but it quite generally slows down the resorption and, thus, also the beginning of the analgesic action.
Moreover, acetylsalicylic acid can be administered practically only orally, but not parenterally, for example, intravenously, intraperitoneally or topically. But precisely because of the quick onset of action and/or the gentle treatment of the gastrointestinal tract, a parenteral administration would often be desirable.